ON THE UNION OF FLEXIBLE FIBUES, ] 85 



they are generally put into warm water, which kills the chrysalis; but when it 

 is preserved, it soon turns to a moth, which lives but a few days, taking no 

 food, and dies after producing eggs for the next season. 



The silk is either yellow or white, but the white is an accidental variety 

 only. By repeated washings, the yellow silk is bleached, and that which is 

 originally white, acquires a more perfect whiteness. Soap is also used for re- 

 moving a gummy substance that accompanies the silk of the cocoons. 



Wool is distinguished into two principal varieties, long and short wool. 

 The longest is from Lincolnshire; it is combed, by means of instruments 

 furnished with a double row of long and sharp teeth of iron or steel; it is re- 

 peatedly drawn from one comb to the other, heat being used in the process, 

 and also a little oil. The fleeces of long wool are generally heavier than those 

 of short wool, but less valuable, on account of their coarseness ; they are 

 used for worsteds, and for cloths in which the separate threads remain visible, 

 as stuifs, shalloons, serges, and tammies. Short wool, on the contrary, is 

 carded, and is used for cloths in which the individual threads are concealed 

 by the projecting fibres. 



The principal use of thread and yarn, when spun, is for the purpose of 

 weaving. The same force of lateral adhesion that retains the twisted fibres 

 of each thread in their situations, is here also employed in giving firmness to 

 the cloth ; and this adhesion is generally increased by the action of any external 

 force, tending to strain the whole texture. 



The first step in weaving is to form a warp, which consists of threads 

 placed side by side, continued through the length of the piece, and sufficient 

 in number to constitute its breadth. This being wound on a beam or roller, 

 in the loom, the threads are drawn through a harness, consisting of loops 

 formed by twine fixed to bars or frames, which elevates and depresses the 

 threads in succession by means of treadles, moved by the feet, in an order 

 which is d liferent, according to the different nature of the intended work; 

 the cross thread or woof, being thrown between them at each alternation, by 

 means of a shuttle, and forced into its place by a batten or comb, made of 



VOL. I. B b 



